Applicability of DNA Barcoding in the Identification of Different Strains in Pyropia yezoensis

Abstract:

In order to find out an effective method to identify Pyropia yezoensis germplasm, we tested the efficacy of four common DNA barcodings—RUBISCO Spacer, UPA, Cox2-3, and ITS-5.8S—in determining the genetic relationships between six strains of P. yezoensis from China and Japan. The four DNA barcodings showed high sequence homologies varying from 97.8% to 100%, and the homology of RUBISCO Spacer was 100%. Four Chinese strains (LS, B4, HT, and TM18) shared the same UPA sequence. However, the barcoding was different from that of the Japanese strains GT and ROS-2 and the homology was 99.2%. The homologies of Cox2-3 and ITS-5.8S sequences were 97.8%-99.2% and 98.4%-99.8% respectively, which were lower than those of RUBISCO Spacer and UPA. Phylogenesis of UPA, Cox2-3 and ITS-5.8S sequences revealed that the four Chinese strains clustered into one branch according to their UPA and ITS-5.8S sequences, whereas the two Japanese strains belonged to another branch. These results were consistent with their actual relationships. Moreover, the four Chinese strains could be further distinguished according to their ITS-5.8S sequences, but were identified as in the same branch with the Cox2-3 barcoding. The results confirmed that ITS-5.8S was the most effective barcoding for identifying P. yezoensis strains in this study